Labels: tests, a11y, priority:medium

Summary
Provide shared helpers to test portals, focus return, and scroll-lock behavior.

Acceptance Criteria

Utility to mount components in custom container.

Helper to assert focus trapping/return.

Integrated into Dialog/DropdownMenu/Tooltip tests.

Test Plan (Implementation Notes)
Framework: Jest + React Testing Library
Files: test-utils/portal.ts
Helpers: focus-trap assertions
Edge cases: nested portals, multiple overlays
Coverage Targets: N/A.

Out of Scope
Visual z-index checks.

Risk
medium – cross-component usage.

Effort
M

References

Components using portal fragments (e.g., SelectPortal.tsx)